Magnetic separation or ore.



F. B. DUTTON & B. E. McKECHNIE.

MAGNETIC SEPARATION OF ORE.

APPLICATION FILED APR. 2. 1912.

1,M6,,140. Patented July 13, 1915.

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PATENT OFFICE- FRANCIS B. DUTTON AND BENJAMIN E. IllllcKECI-INIE, 0FLEBANON, PENNSYLVANIA,

ASSIGNORS T0 PENNSYLVANIA STEEL COMPANY, OF PHILADELPHIA, PENNSYL- VANIAA CORPORATION PENNSYLVANIA.

MAGNETIC SEPARATION or. one.

Patented July 13, 1915..

Application filed April 2, 1912. Serial No. 687,981.

To all whom it may concern:

Be it known that we, FRANCIS and BENJAMIN E. MoKEonNm, citizens of theUnited States, residing at Lebanon, county of Lebanon, and State ofPennsylvania, have invented certain new and useful Improvements inMagnetic Separation of Ore, fully described and representedfln thefollowing specification and the accompanying drawings, forming a part ofthe same.

This invention relates to an improved method of separating magneticmaterial, particularly magnetic iron ore, from material of anon-magnetic nature.

The invention has for its object the novel treatment of crushed magneticiron ore consisting of particles of magnetic iron mixed withnon-magnetic impurities, whereby the magnetic particles of iron may bemore readily and effectively separated from the impurities with whichthey are mixed and removed therefrom than by methods heretoforesuggested, and a better concentrate obtained.

The desired results are obtained by caus ing the magnetic iron ore in acrushed or powdered condition, preferably suspended in water or othersuitable fluid carrier, to

be acted upon by magnets in such a way that the magnetic action on theore is gradual, whereby the magnetic particles are separated from thenon-magnetic particles according to their magneticquality, the purestparticles being first separated from the nonmagnetic particles withwhich they are mixed. Preferably the improved method consists inbringing the mass of magnetic ore and its impurities suspended in thecarrying liquid gradually into the field of a number of magnets ofsubstantially the same and removing the particles asthey are separated,the separation of the particles being effected beneath the surface ofthe carrying liquid and the removal being eifectyi in a directionreverse orcounter to the'direction in which the crushed ore is broughtinto the magnetic field. Preferably also the removed particles aresomewhat dried or drained of the carrying liquid between their removalor separation and their delivery from the apparatus employed incarryingout the method.

l3. Du'r'ron" With this method a very thorough and efiective separationof the magnetic particles is produced, and a higher grade concentrate*obtained, and this method permits of the employment of very simple andconvenient apparatus for carrying out the method.

One suitable and convenient apparatus for practisingthe method consistsgenerally of a tank to which the crushed or powdered ore, suspended inwater or other suitable carrying liquid, issupplied. In the tank is arotating water tight drum of non-magnetic material partially immersed inthe liquid, within which drum stationarily are mounted a plurality ofsuitable magnets. A carrier for removing the magnetic material as it isseparated from the impurities is provided, which may be an endless belt,preferably of canvas or fine mesh wire, encircling the drum, and leadingto a suitable depository for the concentrates. The side walls of thetank at the end thereof where the crushed ore suspended in the carryingliquid is admitted slope or incline toward the drum, so that the crushedore introduced into the tank is brought gradually within the influenceof the magnets in order that as the richer particles are first separatedfrom the impurities by the action of the magnets they are removed by theconveyer or carrier, the magnetic particles being separated according totheir purity, the impurities or sludge settling in the tank and beingdrawn ofi in a suitable manner. I

Such an apparatus in simple form is shown in the accompanying drawing,in which the figure is a vertical section of so much of the apparatus asis necessary for an understanding of the invention.

Referring to this figure, 1 indicates a suitable framework on which theoperative parts of the apparatus are supported. On the framework 1 ismounted a tank construction 2, which may be of suitable configurationfor water, is supplied to the tank 2 through a suitable feed pipe 3delivering to a feed box 4 having a feed opening or slot 5, whichregulates the flow of the ore. From the feed box 4 the ore is delivereda ainst a numbenof bafies 6 on a feed board which, at its lower ordelivery end, is slotted or apertured, as at 8. The baffles insure aneven distribution of the crushed ore insolution or pulp as it is termed,and an even and regular supply to the tank. Within the tank is a drum 10supported on a non-rotating shaft 11 so as to be rotatable, suitablebearings being provided for the shaft. The drum 10 is of non-magneticmaterial, as brass, and is supported so as to be partially immersed, orsubmerged, in the liquid in the tank. The drum is, therefore, watertight. Within the drum are located a plurality of magnets 12, 12 havingsuitable pole pieces 13 arranged to be in close proximity to but freefrom the interior surface of the drum. The magnets 12, 1%, are supportedin any suitable manner, as by spider 14 having arms 15, the spider beingfast on the shaft 11, being fastened thereto as by a set screw 16. Theshaft 11 is provided beyond its bearing, at one end, with a squaredportion 16 (shown in dotted lines) which is adapted to receive a leveror other suitable tool by which the shaft may be turned or rocked in itsbearings and the carried by the shaft adjusted in the drum as desired.The bottom of the tank 2 before referred to comprises walls 17, 18, thewall the drum tangentially so that the space between the drum and thewall of the tank through which the crushed ore is fed narrows, beingwider at the top or feed end and narrowing as it approaches the drum. Bymoving the tank on the rollers 2*, before referred to, the distancebetween the wall of the tank and the drum may be adjusted, as necessary.With this construction the crushed ore is brought gradually under theinfluence of the magnets and the magnetic particles of the iron areseparated out according to their richness, the richest being firstremoved. This results in a better grade of concentrates, and cleanertailings, in that the material may be brought closer to the ma ets andconsequently'through a stronger eld after the bulk of the magneticparticles has been removed, then if the whole separation were made atapproximately one point, in which case the richer portion would beseparated out so violently that many particles of non-magnetic materialwould be drawn out with those magnetic. Furthermore, by feeding the ore,as described tangentially to the drum, and subjecting it to the actionof the magnets as it is so fed, the magnetic particles are separated orpicked out by some of the magnets laterally in a sidewise direction, andthese position of the magnets being at the feed end of the tank. This Q,wall is inclined, or sloped, inclining toward magnets do not have towork directly against gravity. This results in an improved separation,in that the particles falling freely past the magnets are more readilyacted on by them, and the magnets acting to pick the particles outbeneath the surface of the water do not have to overcome the surfacetension of the water and thus may be operated mechanically and to muchgreater advantage. Preferably the opposite wall 18 of the tank likewiseslopes in order to permit the sludge or non-magnetic impurities to bemore readily drawn 0d through a suitable tail pipe 19, the sludgesettling readily and being guided to the tail pipe by the sloping wallsof the tank.

The liquid level in the tank is maintained so that the magnets whicheffect the separation of magnetic iron are below the level of the liquidin the tank. For various reasons it may not be desirable that the liquidlevel in the tank be maintained by adding more or less water to the pulpbefore it enters feed pipe 3. It is preferable that the liquid befurnished from an auxiliary source. To effect this, there is provided asuitable perforated with a suitable source of water supply (not shown)which supplies additional needed water to the tank preferably in theform of a a spray to assist in the even distribution of the feed of thepulp. This water supply pipe 19 is positioned just in front of the feedbox 4, before referred to, so as to evenly distribute the "watersupplied over the pulp as it issues from the box. On the wall 18 of thetank before referred to is a. dam 19 the top of this dam being ofsufficient height so as to maintain the liquid in the tank at thedesired level.

Preferably, in practice, the water is supplied from the pipe 19 in suchquantity as to just flow over this dam 19 this excess escaping through asuitable pipe 19 to the outlet box 19 It may be here observed that themagnets are preferably so adjusted in the drum that one magnet as 12 ispositioned above the level of the liquid in the tank. This magnet doesnot operate to separate the magnetic iron, but acts to hold theseparated particles on the carrier belt and prevents them from fallingback into the tank, the remaining magnets efl'ecting the separation.

Suitable means are provided for removing the magnetic particles from thetank as they are attracted by "the magnets, which. means may be somewhatvaried. A convenwater supply pipe 19 connected ient constructionincludes a carrier which This carrier belt 20 is driven to run in adirection reverse or counter to the direction of feed of the crushedore, as indicated by the arrows. The belt 20 thus carries away thematerial as it is separated out and delivers it to a suitable apparatus,which may consist of an inclined chute 25 mounted on the framework 1from which the concentrates are delivered as desired. The chute 25 islocated below the roll 21, over which the carrier 20 runs. As thecarrier turns about this roll, the major part of the concentrates fallfrom the belt of their own weight into the chute. A portion may,however, adhere to the belt, and to remove it there is provided anysuitable means, as a nozzle 26, for supplying water or air underpressure, which also tends to keep the belt clean.

It is preferable, when the wet method of separation is employed, thatthe concentrates be delivered in as dry a condition as practicable. Therun of the belt is therefore somewhat longer than necessary for theremoval ,of the concentrates from the tank. While the concentrates areto some extent dried by the course of the belt from the drum 10 to theroll 21, they may be much more thoroughly dried by the provision offurther drying means. To this end therefore the carrying belt is made ofcanvas, fine wire mesh or other porous material, and there provided asuction apparatus 27 located under the belt at a suitable point, andconnected with a' suitable suction pump (not shown) so that as theconcentrates pass along on the carrying belt the moisture is to a largeextent removed therefrom.

No claims are herein made -to the apparatus described. This apparatus,however, forms the subj cot-matter of a separate application Serial No.687 ,982, filed April 2, 1912, by us, in which the novel features areclaimed. a i

What is claimed is 1. The method of separating magnetic material fromnonmagnetic, which consists in mixing the material in a crushedcondition with a carrying liquid, feeding the material a downwarddirection past a magnetic field and subjecting it while so fed toinfluence of gravity,

material from nonmagnetic, which consists in mixing the material in acrushed condition with a carrying liquid, feeding the materialtangentially past a magnetic field while beneath the surface of theliquid so that the strength of the magnetic action on the materialincreases progressively and the particles are separated beneath thesurface of the liquid progressively according to their magnetic purity,and then removing the magnetic particles as they are separated,

in a counter direction to that in which they were fed into the magneticfield.

3. The method of separating magnetic material from nonmagnetic, whichconsists in mixing the material in a crushed condition with a carryingliquid, feeding the material tangentially by the action of gravity pasta magnetic field while beneath the surface of the liquid so that thestrength of the magnetic action onthe material increases progressivelyand the particles are separated beneath the surface of the liquidlaterally or in a lateral direction and progressively according to theirmagnetic purity, the nonmagnetic particles continuing under the and thenremoving the magnetic particles as they are separated, in a. counterdirection to that in which they were brought into the magnetic field.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing witnesses.

FRANCIS B. DUTTON. BENJAMIN E. McKECI-INIE.

Witnesses:

HOWARD G. SHIRK, C. Bnssrn LosER.

